基本要求是由样本数据，估计出模型中的参数A和B。

1).估计出应力水平 时的寿命区间估计；

2).由已求得参数A和B，绘制出应力水平 与失效率 的关系曲线

-The basic requirement is provided by the sample data, the estimated model parameters A and B. 1) the estimated stress level life time interval estimation　2) has been obtained by the parameters A and B, draw out the curve of the stress levels and the loss of efficiency